Safety of COVID-19 vaccines during pregnancy: A systematic review and meta-analysis

Neonatal and maternal outcomes of mRNA versus Non-mRNA COVID-19 vaccines in pregnant patients: a systematic review and meta-analysis

Objective

To compare the effectiveness and safety of non-mRNA versus mRNA COVID-19 vaccines on pregnant women and their newborns in a systematic review with meta-analysis.

Data sources

We searched PubMed, Embase, and Cochrane Central in May 2023.

Study selection

The search strategy yielded 4451 results, 16 studies were fully reviewed. We selected case-control studies analysing non-mRNA versus mRNA vaccines. Data collection and analysis: we assessed the risk of bias using the Cochrane Risk of Bias in Non-randomized Studies of Interventions (ROBINS-I) tool. Standardised mean differences were pooled using random-effect models.

Data synthesis

We identified 8 prospective and retrospective studies with a total of 32,153 patients. Non-mRNA vaccines were associated with a higher incidence of fever (OR 2.67; 95% CI 2.08-3.43; p<0.001), and a lower incidence of fetal or neonatal death (OR 0.16; 95% CI 0.08-0.33; p<0.001). In subgroup analyses, the Jansen vaccine (Ad26.COV2.S) was found to have a higher rate of premature labor/delivery (OR 4.48; 95% CI 1.45-13.83; p=0.009) and missed/spontaneous abortion (OR 1.90; 95% CI 1.09-3.30; p=0.02), as compared with the Pfizer (BNT162b2) vaccine.

Conclusion

non-mRNA vaccines are associated with a lower incidence of fetal or neonatal death among pregnant women who receive a Covid19 vaccine, although at an increased rate of pyrexia compared with mRNA vaccines. Other studies are required for better assessment.

PROSPERO

CRD42023421814.

T-cell responses to ancestral SARS-CoV-2 and Omicron variant among unvaccinated pregnant and postpartum women living with and without HIV in South Africa

SARS-CoV-2 cell-mediated immunity remains understudied during pregnancy in unvaccinated Black African women living with HIV (WLWH) from low- and middle-income countries. We investigated SARS-CoV-2-specific T-cell responses 1 month following infection in 24 HIV-uninfected women and 15 WLWH at any stage during pregnancy or postpartum. The full-length spike (FLS) glycoprotein and nucleocapsid (N) protein of wild-type (WT) SARS-CoV-2, as well as mutated spike protein regions found in the Omicron variant (B.1.1.529) were targeted by flow cytometry. WT-specific CD4+ and CD8+ T cells elicited similar FLS- and N-specific responses in HIV-uninfected women and WLWH. SARS-CoV-2-specific T-lymphocytes were predominantly TNF-α monofunctional in pregnant and postpartum women living with and without HIV, with fever cells producing either IFN-γ or IL-2. Furthermore, T-cell responses were unaffected by Omicron-specific spike mutations as similar responses between Omicron and the ancestral virus were detected for CD4+ and CD8+ T cells. Our results collectively demonstrate comparable T-cell responses between WLWH on antiretroviral therapy and HIV-uninfected pregnant and postpartum women who were naïve to Covid-19 vaccination. Additionally, we show that T cells from women infected with the ancestral virus, Beta variant (B.1.351), or Delta variant (B.1.617.2) can cross-recognize Omicron, suggesting an overall preservation of T-cell immunity.

Individual and familial factors associated with mRNA COVID-19 vaccine uptake in pregnancy: A large-scale registry-based linkage study

The association between maternal COVID-19 vaccination in pregnancy and factors such as high risk for severe COVID-19, pre-existing asthma, prior adverse reproductive history, or paternal COVID-19 vaccination during pregnancy, remains unclear. The aim of this study is two-fold: (i) to describe uptake of COVID-19 vaccine during pregnancy by maternal risk for severe COVID-19 and asthma, and (ii) to comprehensively examine individual and familial factors associated with vaccine uptake during pregnancy in Norway. Based on nation-wide registry-linkage data in Norway, we included 101,659 deliveries with gestational length ≥12 weeks, in 2021-2022. Our outcome measure was uptake of at least one dose of mRNA COVID-19 vaccine during pregnancy, using a narrow (first ever dose) and broad (any dose) definition. We fit univariate and multivariate modified Poisson regression models, clustered by county of residency and adjusted for calendar time, to estimate risk ratios (RR) with 95 % Confidence Intervals (CIs). Gestational uptake of any COVID-19 vaccine dose increased from <1 % before mid Aug-2021, to 38.8 % in the rest of 2021, and 48.9 % in 2022. Only 28.8 % and 33.9 % pregnant individuals with high risk for severe COVID-19 or asthma, respectively, received at least one COVID-19 vaccine dose. Paternal COVID-19 vaccination was strongly associated with greater vaccine uptake by pregnant individuals (adjusted RR: 7.2, 95 % CI: 6.8-7.5). Maternal SARS-CoV-2 infection pre-pregnancy (adjusted RR: 0.31, 95 % CI: 0.26, 0.37), familial and individual migrant status were associated with a considerable decreased likelihood of vaccine uptake in pregnancy. History of miscarriage or pregnancy with congenital anomaly were not associated with vaccine uptake. Despite rising COVID-19 vaccine rates in pregnancy, uptake remained low for high-risk individuals. Paternal vaccination, pre-pregnancy infection, migration status, and maternal citizenship were strongly associated with prenatal vaccine uptake. This knowledge can inform tailoring of future vaccination campaigns.

COVID-19 and influenza vaccine uptake among pregnant women in national cohorts of England and Wales

Vaccines against COVID-19 and influenza can reduce the adverse outcomes caused by infections during pregnancy, but vaccine uptake among pregnant women has been suboptimal. We examined the COVID-19 and influenza vaccine uptake and disparities in pregnant women during the COVID-19 pandemic to inform vaccination interventions. We used data from the Oxford-Royal College of General Practitioners Research and Surveillance Centre database in England and the Secure Anonymised Information Linkage Databank in Wales. The uptake of at least one dose of vaccine was 40.2% for COVID-19 and 41.8% for influenza among eligible pregnant women. We observed disparities in COVID-19 and influenza vaccine uptake, with socioeconomically deprived and ethnic minority groups showing lower vaccination rates. The suboptimal uptake of COVID-19 and influenza vaccines, especially in those from socioeconomically deprived backgrounds and Black, mixed or other ethnic groups, underscores the necessity for interventions to reduce vaccine hesitancy and enhance acceptance in pregnant women.

Knowledge, acceptance and concerns regarding COVID-19 vaccination among pregnant women on the east coast of Peninsular Malaysia: A cross-sectional study

Introduction

This prospective cross-sectional study, conducted from 1 April 2022 to 31 October 2022, aimed to assess the knowledge, acceptance and concerns regarding COVID-19 vaccination among pregnant women visiting the Obstetrics and Gynaecology Department of Hospital Universiti Sains Malaysia.

Methods

The study included all pregnant women aged >18 years. Sociodemographic data, information related to COVID-19 and vaccination and information on the knowledge, acceptance and concerns regarding COVID-19 vaccination were collected using a validated questionnaire.

Results

Out of 420 eligible pregnant women, 412 participated in the study, yielding a response rate of 98.1%. Of the respondents, 97.1% had received a COVID-19 vaccine, while 2.9% had not. Approximately 85.2% demonstrated a good understanding of COVID-19 vaccination. Among those vaccinated, 76.8% based their decision on recommendations from healthcare providers or the Ministry of Health. Among those unvaccinated, 91.7% believed that COVID-19 vaccines could harm their pregnancy and baby. Although 51% of the respondents expressed concerns about vaccine safety, 202 still chose to be vaccinated, indicating a willingness to prioritise their health despite apprehensions.

Conclusion

The study found no significant link between acceptance and good knowledge of COVID-19 vaccination. However, income and prior COVID-19 booster vaccination were strongly associated with acceptance. Despite safety concerns, 97.1% of the respondents had received a COVID-19 vaccine. This emphasises the importance of providing comprehensive information and addressing concerns to support informed decision-making among pregnant women. Healthcare providers play a vital role in guiding them through this crucial decision-making process.

Vaccination in pregnancy. Consensus document of the CAV-AEP and the SEGO

During pregnancy, physiological changes in the immune response make pregnant women more susceptible to serious infection, increasing the risk for the mother as well as the foetus, newborn and infant. All women should be correctly and fully vaccinated as they enter their reproductive years, especially against diseases such as tetanus, hepatitis B, measles, rubella and varicella. In addition to the recommended vaccines, in risk situations, inactivated vaccines could be administered to women who were not correctly vaccinated before, while attenuated vaccines are contraindicated. Despite the fact that vaccination during pregnancy is a very important preventive measure and the existing recommendations from public health authorities, scientific societies and health professionals, the vaccination coverage could clearly be improved, especially against influenza and SARS-CoV-2, so any health professional involved in the care of pregnant women should proactively recommend these vaccines. The Spanish Association of Pediatrics (AEP), through its Advisory Committee on Vaccines, and the Spanish Society of Gynaecology and Obstetrics (SEGO) recommend vaccination against the following diseases during pregnancy: against influenza and COVID-19, in any trimester of pregnancy and during the postpartum period (up to 6 months post birth) in women not vaccinated during pregnancy; against pertussis, with the Tdap vaccine, between weeks 27 and 36 of gestation (in the CAV-AEP recommendations, preferably between weeks 27 and 28); and against RSV, with RSVPreF, between weeks 24 and 36 of gestation, preferably between weeks 32 and 36.

Patisiran exposure in early pregnancy: a case report

We describe here the first case of exposure to patisiran treatment, a small interfering RNA molecule, during early pregnancy of a 36-year-old woman with symptomatic hereditary transthyretin-related amyloidosis. There were no major complications during pregnancy and delivery, except for a postpartum hemorrhage due to uterine atony. Vitamin A levels had to be closely monitored during pregnancy, and vitamin A substitution adapted accordingly. There was no sign of minor or major congenital abnormalities of the baby. One month after delivery, the patient showed slight clinical and electrophysiological signs of neuropathy progression due to patisiran treatment withdrawal. Patisiran infusions were resumed 3 months after delivery. Due to the unknown teratogenic potential of patisiran, the risk of neuropathy worsening associated with withholding treatment must of course be weighed against a potential teratogenic risk of treatment during pregnancy. Vitamin A levels need to be closely assessed, and substitution must be adapted accordingly, to avoid embryofetal adverse outcome due to vitamin A deficiency or toxicity.

Estimating COVID-19 vaccine acceptance in pregnant and lactating women: a cross-sectional study in Lebanon

BACKGROUND

The COVID-19 pandemic highlights vaccination's critical role in reducing morbidity and mortality, depending on public attitude. This study aims to identify the estimates of COVID-19 vaccine acceptance in pregnant and lactating women, as well as associated potential factors.

METHODS

A cross-sectional study was conducted between August and September 2021, through an online survey and with a paper survey distributed in gynecology and pediatric clinics. Pregnant and breastfeeding women aged 18 years and above were recruited. The attitude scale was created specifically for evaluating attitudes towards the COVID-19 vaccine.

RESULTS

In total, 207 women participated, with 132 breastfeeding, 74 pregnant and 1 experiencing both conditions. Of these, one hundred and twenty women (58%) considered themselves at risk for COVID-19 infection. In addition, 51.7% (n = 107) of women expressed the intent to receive the vaccine once available. A multivariable linear regression was conducted taking the COVID-19 vaccination attitude scale as a dependent variable. The results revealed an R-squared value of 0.558, indicating that approximately 55.8% of the variance in the attitude scale was accounted for by the included predictors. The results showed that preventive measures (ß=2.25, 95% Confidence Interval (CI) [1.02; 3.48], p < 0.001), preference for vaccines made in Europe and America (ß=1.23; 95% CI [0.69-1.77], p < 0.001), protect yourself for getting sick (ß=4.22, 95% Confidence Interval (CI) [2.83; 5.61], p < 0.001) and belief in the importance of vaccination for themselves and their baby (ß=3.49; 95% CI [2.01; 4.98], p < 0.001) were associated with a positive attitude towards vaccination. Conversely, experiencing a previous bad reaction to a vaccine (ß= -1.35; 95% CI [0.85-1.85], p < 0.001) and concerns regarding COVID-19 vaccine safety (ß= -4.09; 95% CI [-5.98; -2.21], p < 0.001) were associated with a negative attitude towards vaccination.

CONCLUSION

Our findings reveal that COVID-19 vaccine acceptability among pregnant and breastfeeding women, amidst the pandemic was insufficient to meet community immunity. The identified reasons for vaccine reluctance, notably concerns about safety for both personal health and the health of their pregnancy or newborns, along with insufficient information about the vaccine, underscore the pressing need to address these factors to improve immunization rates.

Pregnancy Outcomes among Pregnant Persons after COVID-19 Vaccination: Assessing Vaccine Safety in Retrospective Cohort Analysis of U.S. National COVID Cohort Collaborative (N3C)

COVID-19 vaccines have been shown to be effective in preventing severe illness, including among pregnant persons. The vaccines appear to be safe in pregnancy, supporting a continuously favorable overall risk/benefit profile, though supportive data for the U.S. over different periods of variant predominance are lacking. We sought to analyze the association of adverse pregnancy outcomes with COVID-19 vaccinations in the pre-Delta, Delta, and Omicron SARS-CoV-2 variants' dominant periods (constituting 50% or more of each pregnancy) for pregnant persons in a large, nationally sampled electronic health record repository in the U.S. Our overall analysis included 311,057 pregnant persons from December 2020 to October 2023 at a time when there were approximately 3.6 million births per year. We compared rates of preterm births and stillbirths among pregnant persons who were vaccinated before or during pregnancy to persons vaccinated after pregnancy or those who were not vaccinated. We performed a multivariable Poisson regression with generalized estimated equations to address data site heterogeneity for preterm births and unadjusted exact models for stillbirths, stratified by the dominant variant period. We found lower rates of preterm birth in the majority of modeled periods (adjusted incidence rate ratio [aIRR] range: 0.42 to 0.85; p-value range: <0.001 to 0.06) and lower rates of stillbirth (IRR range: 0.53 to 1.82; p-value range: <0.001 to 0.976) in most periods among those who were vaccinated before or during pregnancy compared to those who were vaccinated after pregnancy or not vaccinated. We largely found no adverse associations between COVID-19 vaccination and preterm birth or stillbirth; these findings reinforce the safety of COVID-19 vaccination during pregnancy and bolster confidence for pregnant persons, providers, and policymakers in the importance of COVID-19 vaccination for this group despite the end of the public health emergency.

In Utero Exposure to Maternal COVID-19 Vaccination and Offspring Neurodevelopment at 12 and 18 Months

Importance

Uptake of COVID-19 vaccines among pregnant individuals was hampered by safety concerns around potential risks to unborn children. Data clarifying early neurodevelopmental outcomes of offspring exposed to COVID-19 vaccination in utero are lacking.

Objective

To determine whether in utero exposure to maternal COVID-19 vaccination was associated with differences in scores on the Ages and Stages Questionnaire, third edition (ASQ-3), at 12 and 18 months of age.

Design, Setting, and Participants

This prospective cohort study, Assessing the Safety of Pregnancy During the Coronavirus Pandemic (ASPIRE), enrolled pregnant participants from May 2020 to August 2021; follow-up of children from these pregnancies is ongoing. Participants, which included pregnant individuals and their offspring from all 50 states, self-enrolled online. Study activities were performed remotely.

Exposure

In utero exposure of the fetus to maternal COVID-19 vaccination during pregnancy was compared with those unexposed.

Main Outcomes and Measures

Neurodevelopmental scores on validated ASQ-3, completed by birth mothers at 12 and 18 months. A score below the established cutoff in any of 5 subdomains (communication, gross motor, fine motor, problem solving, social skills) constituted an abnormal screen for developmental delay.

Results

A total of 2487 pregnant individuals (mean [SD] age, 33.3 [4.2] years) enrolled at less than 10 weeks' gestation and completed research activities, yielding a total of 2261 and 1940 infants aged 12 and 18 months, respectively, with neurodevelopmental assessments. In crude analyses, 471 of 1541 exposed infants (30.6%) screened abnormally for developmental delay at 12 months vs 203 of 720 unexposed infants (28.2%; χ2 = 1.32; P = .25); the corresponding prevalences at 18 months were 262 of 1301 (20.1%) vs 148 of 639 (23.2%), respectively (χ2 = 2.35; P = .13). In multivariable mixed-effects logistic regression models adjusting for maternal age, race, ethnicity, education, income, maternal depression, and anxiety, no difference in risk for abnormal ASQ-3 screens was observed at either time point (12 months: adjusted risk ratio [aRR], 1.14; 95% CI, 0.97-1.33; 18 months: aRR, 0.88; 95% CI, 0.72-1.07). Further adjustment for preterm birth and infant sex did not affect results (12 months: aRR, 1.16; 95% CI, 0.98-1.36; 18 months: aRR, 0.87; 95% CI, 0.71-1.07).

Conclusions and Relevance

Results of this cohort study suggest that COVID-19 vaccination was safe during pregnancy from the perspective of infant neurodevelopment to 18 months of age. Additional longer-term research should be conducted to corroborate these findings and buttress clinical guidance with a strong evidence base.

Planning for the future of maternal immunization: Building on lessons learned from the COVID-19 pandemic

As the worldwide COVID-19 pandemic unfolded, the clinical and public health community raced to understand SARS-CoV-2 infection and develop life-saving vaccines. Pregnant persons were disproportionately impacted, experiencing more severe illness and adverse pregnancy outcomes. And yet, when COVID-19 vaccines became available in late 2020, safety and efficacy data were not available to inform their use during pregnancy because pregnant persons were excluded from pre-authorization clinical trials. Concerns about vaccine safety during pregnancy and misinformation linking vaccination and infertility circulated widely, creating a lack of vaccine confidence. Many pregnant people initially chose not to get vaccinated, and while vaccination rates rose after safety and effectiveness data became available, COVID-19 vaccine acceptance was suboptimal and varied across racial and ethnic distribution of the pregnant population. The COVID-19 pandemic experience provided valuable insights that can inform current and future approaches to maternal vaccination against.

COVID-19 Vaccine Safety Technical (VaST) Work Group: Enhancing vaccine safety monitoring during the pandemic

During the COVID-19 pandemic, candidate COVID-19 vaccines were being developed for potential use in the United States on an unprecedented, accelerated schedule. It was anticipated that once available, under U.S. Food and Drug Administration (FDA) Emergency Use Authorization (EUA) or FDA approval, COVID-19 vaccines would be broadly used and potentially administered to millions of individuals in a short period of time. Intensive monitoring in the post-EUA/licensure period would be necessary for timely detection and assessment of potential safety concerns. To address this, the Centers for Disease Control and Prevention (CDC) convened an Advisory Committee on Immunization Practices (ACIP) work group focused solely on COVID-19 vaccine safety, consisting of independent vaccine safety experts and representatives from federal agencies - the ACIP COVID-19 Vaccine Safety Technical Work Group (VaST). This report provides an overview of the organization and activities of VaST, summarizes data reviewed as part of the comprehensive effort to monitor vaccine safety during the COVID-19 pandemic, and highlights selected actions taken by CDC, ACIP, and FDA in response to accumulating post-authorization safety data. VaST convened regular meetings over the course of 29 months, from November 2020 through April 2023; through March 2023 FDA issued EUAs for six COVID-19 vaccines from four different manufacturers and subsequently licensed two of these COVID-19 vaccines. The independent vaccine safety experts collaborated with federal agencies to ensure timely assessment of vaccine safety data during this time. VaST worked closely with the ACIP COVID-19 Vaccines Work Group; that work group used safety data and VaST's assessments for benefit-risk assessments and guidance for COVID-19 vaccination policy. Safety topics reviewed by VaST included those identified in safety monitoring systems and other topics of scientific or public interest. VaST provided guidance to CDC's COVID-19 vaccine safety monitoring efforts, provided a forum for review of data from several U.S. government vaccine safety systems, and assured that a diverse group of scientists and clinicians, external to the federal government, promptly reviewed vaccine safety data. In the event of a future pandemic or other biological public health emergency, the VaST model could be used to strengthen vaccine safety monitoring, enhance public confidence, and increase transparency through incorporation of independent, non-government safety experts into the monitoring process, and through strong collaboration among federal and other partners.

Assessing the Impact of COVID-19 Vaccination on Preterm Birth: A Systematic Review with Meta-Analysis

During the coronavirus diseases 2019 (COVID-19) pandemic, the safety and efficacy of vaccination during pregnancy, particularly regarding the risk of preterm birth, have been a subject of concern. This systematic review aims to evaluate the impact of COVID-19 vaccination on preterm birth risk and to inform clinical practice and public health policies. Following PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, a database search included PubMed, Embase, and Scopus, conducted up until October 2023. Inclusion criteria focused on studies that examined COVID-19 vaccination during pregnancy and its correlation with preterm birth, defined as a birth before 37 weeks of gestation. Six studies met these criteria, encompassing 35,612 patients. A quality assessment was performed using the Newcastle-Ottawa Scale and the Cochrane Collaboration's tool, with the risk of bias evaluated via a funnel plot analysis and an Egger's regression test. The studies demonstrated geographical diversity, mainly from Israel, Romania, and the United States, with a blend of prospective and retrospective designs. The patient cohort's mean age was 31.2 years, with common comorbidities such as gestational diabetes and obesity affecting 9.85% of the total population. The vaccination types varied across the studies, with BNT162b2 being the most used. The results indicated a low heterogeneity among the included studies, evidenced by a Cochran's Q statistic of 2.10 and an I2 statistic of 13%. The meta-analysis yielded a pooled odds ratio (OR) for a preterm birth risk post-vaccination of approximately 1.03 (95% CI: 0.82-1.30), suggesting no significant increase in preterm birth risk was associated with COVID-19 vaccination. Notable findings included a low preterm birth rate (as low as 0.6% and up to 6.1%) with minimal differences in neonatal outcomes, such as birth weight and APGAR (appearance, pulse, grimace, activity, and respiration) scores between vaccinated and unvaccinated groups. This study concludes that a COVID-19 vaccination during pregnancy does not significantly increase the risk of preterm birth. These findings are crucial for reassuring healthcare providers and pregnant women about the safety of COVID-19 vaccines and supporting their use in public health strategies during the pandemic.

Discovery and development of COVID-19 vaccines and therapeutics: nonclinical perspectives

The development and regulatory review of BNT162b2, a COVID-19 vaccine, and PaxlovidTM (nirmatrelvir tablets/ritonavir tablets), a COVID-19 therapeutic, are benchmarks for accelerated innovation during a global pandemic. Rapid choice of the SARS-CoV-2 spike protein and main protease (Mpro) as targets for the vaccine and therapeutic, respectively, leveraged the available knowledge of the biology of SARS-CoV-2 and related viruses. The nonclinical immunogenicity and safety of BNT162b2 was rigorously assessed. Likewise, a comprehensive nonclinical safety assessment was conducted for the therapeutic candidates, lufotrelvir (PF-07304814) and nirmatrelvir (PF-07321332). The development and regulatory review of BNT162b2 and Paxlovid was enabled through close collaboration of the pharmaceutical industry with regulatory agencies and public health organizations. This experience highlights approaches that could be adopted for pandemic preparedness including risk-based investment strategies, conduct of activities in parallel that normally are conducted sequentially, quick kill decisions, simultaneous evaluation of multiple candidates, and use of flexible, established vaccine platforms.

Risk of Severe Maternal Morbidity Associated With Severe Acute Respiratory Syndrome Coronavirus 2 Infection During Pregnancy

Background

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection during pregnancy increases the risk of adverse fetal and neonatal outcomes, but the contribution to severe maternal morbidity (SMM) has been less frequently documented.

Methods

We conducted a national cohort study of 93 624 deliveries occurring between 11 March 2020 and 1 July 2021 using medical claims information from the OptumLabs Data Warehouse. SARS-CoV-2 infection was identified from diagnostic and laboratory testing claims records. We identified 21 SMM conditions using International Classification of Diseases, Tenth Revision, Clinical Modification and procedure codes and compared SMM conditions by SARS-CoV-2 status using Poisson regression with robust variance, adjusting for maternal sociodemographic and health factors, onset of labor, and week of conception.

Results

Approximately 5% of deliveries had a record of SARS-CoV-2 infection: 27.0% <7 days before delivery, 13.5% within 7-30 days of delivery, and 59.5% earlier in pregnancy. Compared to uninfected pregnancies, the adjusted risk of SMM was 2.22 times higher (95% confidence interval [CI], 1.97-2.48) among those infected <7 days before delivery and 1.66 times higher (95% CI, 1.23-2.08) among those infected 7-30 days before delivery. The highest risks were observed for acute respiratory distress syndrome (adjusted risk ratio [aRR], 13.24 [95% CI, 12.86-13.61]) and acute renal failure (aRR, 3.91 [95% CI, 3.32-4.50]).

Conclusions

COVID-19 is associated with increased rates of SMM.

Effectiveness and Safety of COVID-19 Vaccination During Preconceptional and Preclinical Pregnancy Period: A National Population Study

BACKGROUND

We aimed to assess the risk of maternal severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and early abortive outcomes after the association between coronavirus disease 2019 (COVID-19) vaccination during the preconceptional period and preclinical pregnancy, which are likely to be inadvertent vaccination.

METHODS

We used data from the Korea Disease Control and Prevention Agency-COVID19-National Health Insurance Service cohort from December 2020 to December 2021. The vaccinated pregnant women were matched to unvaccinated pregnant controls at a 1:4 ratio. The risks of SARS-CoV-2 infection and intensive care unit (ICU) admission within 14 days of infection were analyzed to assess its effectiveness. For safety measures, the adjusted relative risks (aRRs) of early abortive outcomes for the first COVID-19 vaccination during the preconceptional and preclinical periods were calculated considering covariates. We compared the risk of early abortion between mRNA and viral vector vaccines.

RESULTS

The overall COVID-19 vaccination rates during the preconceptional period and preclinical pregnancy were 3.1% (6,662/215,211) and 2.6% (5,702/215,211), respectively. The cumulative incidence of ICU admission within 14 days of SARS-CoV-2 infection was 6/100,000 in the unvaccinated group, whereas there were no ICU admissions in the vaccinated groups. The risks of early abortive outcomes were not significantly different between the preconceptional vaccination group and the unvaccinated group (aRR, 1.04; 95% confidence interval [CI],0.99-1.10) or between preclinical pregnancy vaccination and their matched controls (1.02; 95% CI, 0.96-1.08). mRNA and viral vector vaccines have shown similar risks for early abortive outcomes and miscarriages.

CONCLUSION

Our findings have provided compelling evidence regarding the effectiveness and safety of COVID-19 vaccination prior to and during early pregnancy. Further research is required to extend the safety and efficacy profiles of COVID-19 vaccines to pregnant women and their babies.

Developmental and reproductive safety of Advax-CpG55.2™ adjuvanted COVID-19 and influenza vaccines in mice

SpikoGen® is a recombinant spike protein vaccine against COVID-19 that obtained marketing authorization in the Middle East on October 6th, 2021, becoming the first adjuvanted protein-based COVID-19 vaccine of its type to achieve approval. SpikoGen® vaccine utilizes a unique adjuvant Advax-CpG55.2, which comprises delta inulin and CpG55.2 oligonucleotide, a synthetic human toll-like receptor (TLR)-9 agonist. As part of a safety assessment, developmental and reproductive toxicity (DART) studies were undertaken in mice of Advax-CpG55.2 adjuvanted formulations including SpikoGen®, a H7 hemagglutinin influenza vaccine (rH7HA), the bivalent combination of SpikoGen® and rH7HA, and a next-generation quadrivalent spike protein vaccine. In the first study, vaccines were administered intramuscularly to pregnant dams on gestation days (GD) 6.5 and 12.5, and in the second two doses were given in the pre-mating period with a further two doses during gestation. The doses used in the pregnant mice were 250-1000 times the usual human doses on a weight for weight basis. Strong serum antibody responses with neutralizing activity against the relevant virus were seen in the immunized dams and also at the time of weaning in the sera of their pups, consistent with robust maternal antibody transfer. No adverse effects of any of the vaccine formulations were observed in the immunized dams or their pups. Notably, there were no adverse effects of any of the Advax-CpG55.2 adjuvanted vaccines on female mating performance, fertility, ovarian or uterine parameters, embryo-fetal or postnatal survival, fetal growth, or neurofunctional development. No evidence of antigen interference was observed when SpikoGen® vaccine was mixed and co-administered with influenza hemagglutinin vaccine to pregnant dams. Together with the strong safety profile of SpikoGen® vaccine seen in adults and children in human trials, this DART study data supports the safety of Advax-CpG55.2 adjuvanted COVID-19 and influenza vaccine in women of childbearing potential including during pregnancy.